The invention relates to a marine propulsion gearcase with water inlets and a water passage supplying cooling sea water to the water pump for cooling the engine.
As known in the art, water inlets are provided by holes or slots in the right and left sides of the gearcase and supply sea water to a vertical water passage which in turn supplies the water to the water pump thereabove. Turbulence caused by jets of water from inlet openings on one side of the gearcase can adversely affect performance of inlet openings on the other side of the gearcase. This is known as cross-over from side to side. For example, during a turn when one side of the gearcase is subjected to higher water pressure than the other side, water entering the high pressure water inlet side can be pulled out the other low pressure side. Also, when operating at less than fully submerged heights, there may be short circuited air flow cross-over.
The present invention provides a dividing wall in the water passage, which wall extends substantially above the topmost of the right and left water inlet openings and directs water flow from the openings upwardly and only allows merger of the water flow from the left and right sets of openings to join in the water passage at a point spaced substantially above the topmost of the water inlet openings.